JPH04355700A - Brushless synchronous generator - Google Patents

Abstract

PURPOSE:To perform initial excitation of an AC exciter without requiring DC power supply by inducing an exciting voltage in an armature winding being rotated through a permanent magnet and rectifying thus induced exciting voltage to produce a voltage for initially exciting a synchronous generator. CONSTITUTION:Upon start of a synchronous generator 1, an AC power is induced in a permanent magnet armature winding 13 rotating therewith by means of a permanent magnet 12. Thus induced AC power is rectified through a rotary rectifier 2 to produce power for exciting the field winding 1a of the synchronous generator 1. Consequently, initial excitation of an AC exciter can be performed without requiring DC power supply for initial excitation and the capacity of AC exciter can be reduced. According to the invention, a downsized inexpensive generator unit can be realized.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless synchronous power generator that enables initial excitation of an AC exciter without using a DC power supply.

0002

[Prior Art] Fig. 5 is a single line diagram showing a conventional brushless synchronous generator device. It is a rotating rectifier. 3 is an armature winding of the AC exciter, and 4a and 4b are field windings of the AC exciter, which constitute an AC exciter 4. Further, 5 is a brushless synchronous generator, 6 is a DC power supply for initial excitation, 7 is an automatic voltage regulator (AVR) that adjusts the terminal voltage of the synchronous generator to a constant level, 8
1 is an excitation transformer, 9a and 9b are rectifiers, 10 is a switch that supplies and cuts off DC power to the field winding, 11 is a brushless excitation device, and 14a and 14b are current transformers for excitation of the generator. .

Next, the operation will be explained. First, when starting the synchronous generator 1, the switch 10 is closed. As a result, an excitation current flows from the DC power supply 6 for initial excitation to the field winding 4a, and the AC power induced in the armature winding 3 by this excitation current is rectified by the rotary rectifier 2. This rectified current is supplied to the field winding 1a to excite it, thereby causing the synchronous generator 1 to generate electricity. On the other hand, when the voltage generated by the synchronous generator 1 rises to a specified voltage level, the automatic voltage regulator 7 is operated via the excitation transformer 8 due to the generated voltage, and the voltage regulated by the automatic voltage regulator 7 is The field winding 4 is excited via the rectifier 9a, and after this self-excitation starts, the DC power supply 6 is disconnected from the field winding 4a by the switch 10. In addition, the exciting current at the time of generator load is transmitted to the field winding 4a through current transformers 14a and 14b.
, 4b.

0004

[Problems to be Solved by the Invention] Since the conventional brushless synchronous power generator is constructed as described above, when starting the synchronous generator 1, a DC power supply with a sufficiently large capacity is required for the initial excitation of the AC exciter. It is necessary to use 6,
Further, there is a problem in that it is necessary to automatically supply and cut off power from the DC power supply 6 to the field winding 4a. Note that a technology similar to such a conventional brushless power generator is disclosed in Japanese Patent Publication No. 63-22141.

This invention has been made to solve the above-mentioned problems, and it is possible to perform initial excitation of an AC exciter without preparing a DC power supply for initial excitation. The purpose of the present invention is to obtain a brushless synchronous power generation device that can reduce the capacity of the generator.

[0006]

[Means for Solving the Problems] A brushless synchronous power generator according to the present invention includes a permanent magnet armature winding of an AC exciter that is initially excited by a permanent magnet, and an excitation voltage generated in the permanent magnet armature winding. A synchronous generator in which a field winding for the generator is excited by the excitation current obtained by rectifying the AC exciter, and the excitation voltage of the AC exciter is increased by being excited by the voltage generated by the synchronous generator. At least two of the AC exciters
and a field winding, and when the voltage generated by the synchronous generator exceeds a preset minimum operating voltage of the automatic voltage regulator, the excitation voltage is controlled to the set level. It is designed to be supplied to one side of the field winding of the AC exciter.

[0007]

[Operation] The AC exciter according to the present invention uses a permanent magnet to generate an excitation voltage in a rotating armature winding, and a synchronous generator is initially excited by a voltage obtained by rectifying this excitation voltage. In addition, the output voltage of the synchronous generator is directly supplied to one field winding through a transformer without going through an automatic voltage regulator, so that voltage fluctuations due to load fluctuations of the synchronous generator can be Try to keep it small.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a synchronous generator, and 2 is a rotating rectifier that supplies DC excitation current to the field winding 1a of the synchronous generator 1. 4a and 4b are field windings of an AC exciter, 5 is a brushless synchronous generator, 7 is an automatic voltage regulator (AVR) that adjusts the terminal voltage of the synchronous generator to a constant level, 8 is an excitation transformer, 9a, 9b is a rectifier, 11 is a brushless excitation device, 1
4a and 14b are current transformers for excitation of the generator. Also, 1
2 is a permanent magnet, 13 is an armature winding of an AC exciter as a permanent magnet armature winding arranged close to this permanent magnet 12; 13, field windings 4a and 4b constitute an AC exciter 4. Further, FIGS. 2 and 3 show the permanent magnet 12
FIG. 2 is a front sectional view and a side sectional view of an AC exciter in which the AC exciter is attached to the stator side.

Next, the operation will be explained. First, when the synchronous generator 1 is started, alternating current power is induced by the permanent magnet 12 in the permanent magnet armature winding 13 that rotates together with the synchronous generator 1. This AC power is rectified by a rotary rectifier 2 and excites the field winding 1a of the synchronous generator 1. Therefore, a voltage is generated at the terminals of the synchronous generator 1. This voltage increases in proportion to the rotation speed of the synchronous generator 1, and the automatic voltage regulator 7 operates near the rated rotation speed. Further, due to the excitation current from the automatic voltage regulator 7, the terminal voltage of the synchronous generator 1 increases to the rated voltage.

FIG. 4 shows the relationship between the excitation current and the generator terminal voltage at this time, and the rated voltage is expressed as Vn. According to this, the exciting current Ifp generated by the permanent magnet 12
As a result, the terminal voltage Vp of the synchronous generator 1 gradually increases beyond the minimum operating voltage Va of the automatic voltage regulator 7, but during idling (low speed rotation), the permanent magnet 1
2, the output of the permanent magnet 12 is set so that the terminal voltage (for example, Vi) is lower than the lowest operating voltage Va of the automatic voltage regulator 7. When a load current flows through the load circuit of the synchronous generator 1, the load excitation current is supplied to each field winding 4a, 4b via the AC generators 14a, 14b. Here, two current transformers 14a
, 14b are provided because a part of the current change due to load fluctuation is directly supplied to the field winding 4b without going through the automatic voltage regulator 7, thereby increasing the power of the synchronous generator 1. This is to reduce changes in voltage fluctuations due to load fluctuations.

[0011]

As described above, according to the present invention, the permanent magnet armature winding of an AC exciter is initially excited by a permanent magnet, and the excitation voltage generated in the permanent magnet armature winding is rectified. A synchronous generator whose field winding for the generator is excited by the obtained excitation current, and an AC exciter which is excited by the voltage generated by the synchronous generator to increase the excitation voltage of the AC exciter. at least two field windings, and the excitation voltage for controlling the voltage to a set level when the voltage generated by the synchronous generator exceeds a preset minimum operating voltage of the automatic voltage regulator. is configured to be supplied to one of the field windings of the AC exciter, thereby eliminating the need for DC power supply equipment for initial excitation, and further reducing the capacity of the exciter, resulting in a small and inexpensive power generation device. What you can do is what you get.

[Brief explanation of drawings]

FIG. 1 is a single line diagram showing a brushless synchronous power generator according to an embodiment of the present invention.

FIG. 2 is a front sectional view showing a part of the AC exciter according to the invention.

FIG. 3 is a side sectional view showing a part of the AC exciter according to the invention.

FIG. 4 is a special diagram showing the relationship between the excitation current generated by the permanent magnet and the generator terminal voltage in the present invention.

FIG. 5 is a single line diagram showing a conventional brushless synchronous power generator.

[Explanation of symbols] 1. Synchronous generator 4 AC exciter 4a Field winding 4b Field winding 7 Automatic voltage regulator 12 Permanent magnet 13 Permanent magnet armature winding

Claims (1)

[Claims] Claim 1: A permanent magnet armature winding of an AC exciter that is initially excited by a permanent magnet, and a permanent magnet armature winding of an AC exciter that is initially excited by a permanent magnet;
a rotary rectifier that rectifies the excitation voltage generated in the permanent magnet armature winding; a synchronous generator in which a field winding for a generator is excited by the excitation current rectified by the rotary rectifier; at least two field windings of the AC exciter that are excited by the voltage generated by the synchronous generator to increase the excitation voltage of the AC exciter; and a preset minimum operation of the voltage generated by the synchronous generator. and an automatic voltage regulator that supplies the excitation voltage to one of the field windings of the AC exciter to control the voltage to a set level when the voltage exceeds the set level.